Electric fuel pumps for motor vehicles commonly include a tubular outer housing or shell, a pump in the shell at one end thereof, an end housing in the shell at the other end thereof, and an electric motor in the shell between the pump and the end housing. The electric motor consists of an armature supported on the shell for rotation about a longitudinal centerline thereof and a magnet assembly around the armature including a tubular cylindrical flux carrier between the pump and the end housing and a pair of permanent field magnets. Current is conducted to the armature through brushes on the end housing bearing against a commutator on the armature in a plane perpendicular to the longitudinal centerline of the shell.
To locate the magnets angularly relative to the brushes around the inner surface of the flux carrier, some prior electric fuel pumps include a long plastic lug molded integrally on the end housing and projecting into the flux carrier. A spring between the magnets thrusts the magnets in opposite directions against opposite edges of the plastic lug. In these prior constructions, the end housing also has a plurality of short lugs which limit how close to the end housing the magnets may be located after the end housing is installed on the shell.
In another prior electric fuel pump, a plastic cage is closely received inside the flux carrier with a lug on the cage received in a slot in the flux carrier to establish the position of the cage relative to the flux carrier. The cage has a pair of windows therein which receive respective ones of the magnets. One edge of each window is an integral spring which urges the corresponding magnet against the opposite edge of the window. In this prior construction, the angular location of the brushes relative to the magnets is established indirectly through the flux carrier, i.e. by reception of a lug on the end housing on which the brushes are supported in the aforesaid slot in the flux carrier.
A magnet assembly according to this invention features simple, positive location of the magnets and is an improvement relative to the above described magnet locating apparatus of prior electric fuel pumps.